Just read an interesting book by a Kent Crowley, called 'Surf Beat' - 'Rock'n'Roll's Forgotten Revolution' - published this year, about the history of surf music guitar instrumental in the USA from about '58 to the present time.(ISBN is 978-1-61713-007-6)
As expected there are very few references to the Shads, as it centres on folk like Dick Dale, Surfaris, Chantays, Beach Boys etc.
However, there are interesting comments about the gear used - mainly Fender guitars, amps and reverb units of course.
Also there are some quotes about the strings which Fender fitted as original equipment to Strats, Jazzmasters, Jaguars etc in that era. Evidently the majority of surf music players used stock guitars with strings as supplied- heavy flatwounds. (This included the Beach Boys who were playing a lot of instrumentals back then.)
Apparently Ernie Ball had his guitar shop in LA and noticed a few people were putting together lighter gauge sets with plain thirds, banjo firsts etc (Eddie Cochran used to get him to make up light gauge sets for his Gretsch) and he asked Fender why they didn't fit them and sell more guitars!.
Fender replied that the Strat pickups were designed for optimum performance wth heavy gauge flatwounds (13-56 or so) as these were the best available 'premium' strings available back then- the pickups were wound to enhance the sound of the flatwounds and were 'voiced' accordingly to give a very sharp treble response to balance the inherent dead sound of the flatwounds.
This anecdotal evidence was confirmed by a Chris Fleming of Fender.
Make of this what you will....perhaps the flatwounds were fitted as standard factory issue to 34346?